In a known X-ray apparatus of the described kind (German Pat. Spec. No. 736,294), the carriage can be freely displaced along the ceiling. The electric motor is mounted on the carriage, but does not drive the carriage only directly. The carriage searches for its new end position after of the patient table moves. Consequently, due to its mass inertia, the carriage is liable to travel beyond the desired position after which it returns to this position while jerking the cable as well as the X-ray source and image detector.